The increasing commercialization of agriculture in Tonga has led to the adoption
of agricultural practices that favor short-term monetary gain over the traditional
techniques associated with more sustainable forms of agroforestry. Newer forms
of cultivation and the overuse of the relatively small amounts of land available for
commercial development will almost certainly lead to greater environmental deterioration
than is now evident. The shortage of available land arises largely from
the tenure system instituted last century, which distributes land by hereditary
entitlement. Until recently this system has been considered the most equitable in
the Pacific Islands, but it is now encouraging misuse of land. Because of population
growth, proportionally fewer eligible men can now acquire garden land. At
the same time, noble estate-holders still control large tracts of land, and thousands of customary allotments that have been allocated formally to individuals are underused because the registered landholder has moved away, often overseas.
The land that is available for reallocation tends, therefore, to fetch high rents for
only short lease periods. As a result, wealthy businessmen and nobles who control
land have become the more successful agricultural entrepreneurs. Smaller
operators obtain land through informal, often insecure, arrangements. Commercial
growers often try to increase cash returns on crop yields by shortening fallow
periods, thereby reducing the quality of both soil nutrients and revegetation.
Trees are felled to facilitate mechanical tillage, a practice that disturbs soil structures.
The increasing use of biocides, particularly on recently introduced monocultures,
will further affect the environment in ways that are not yet adequately
understood.